This invention relates to a magnetoelectric converter, sometimes referred to as a Hall generator, utilizing the familiar Hall effect for providing an output voltage proportional to the strength of the magnetic field applied.
The Hall generator has been known and used extensively which gives a voltage, known as Hall voltage, in proportion to magnetic field strength. The Hall generator therefore lends itself to use as a magnetism detector. Additionally, positioned contiguous to a path of electric current, the Hall generator will be acted upon by the magnetic field appearing in proportion to the magnitude of the electric current flowing through the path, thereby putting out a voltage proportional to the field strength and hence to the current magnitude.
As heretofore constructed, however, such Hall-effect devices have still left much to be desired. There have been consistent demands for devices of improved sensitivity to magnetic fields, and of improved noise immunity, in addition, of course, to those devices that meet all these requirements but that are nevertheless inexpensive.
The present invention aims at improving the noted important attributes of Hall-effect magnetoelectric converters.
Briefly, the invention may be summarized as a magnetoelectric converter utilizing the Hall-effect for detecting a magnetic field or electric current. Included is a magnetic layer formed on a metal-made baseplate, the magnetic layer being higher in magnetic permeability than the base-plate. Semiconductor means including a Hall-effect device for generating a voltage proportional to the strength of an applied magnetic field, are formed on the baseplate, either directly or via the magnetic layer. An encapsulation of electrically insulating material envelops the baseplate and the magnetic layer and the semiconductor means.
In one embodiment of the invention the magnetic layer is formed on one of the pair of opposite major surfaces of the baseplate, and the semiconductor means are formed on the baseplate via the magnetic layer. Alternatively, however, the semiconductor means may be formed directly on the other surface of the baseplate. As an additional alternative, a pair of magnetic layers may be formed on both major surfaces of the baseplate.
For the best results the baseplate may be fabricated from copper, with or without nickel plating, and the magnetic layer from Permalloy.
The provision of the magnetic layer or layers on the metal-made baseplate according to the invention has proved to reduce the magnetic resistance of the flux path. The Hall-effect device is thus rendered more sensitive to the magnetic field, developing a voltage in exact proportion to the field strength.
The metal-made baseplate with the magnetic layer or layers thereon has also proved to serve the additional purpose of effectively shielding the Hall-effect device from external magnetic or electromagnetic noise. The baseplate will absorb high-frequency noise as eddy current flows therein, whereas the magnetic layer or layers will provide a bypass or bypasses for lower-frequency noise. Hence the improved noise immunity of the device.
The above and other objects, features and advantages of this invention will become more apparent, and the invention itself will best be understood, from a study of the following detailed description and appended claims, with reference had to the attached drawings showing the preferred embodiments of the invention.